The invention relates to a recording apparatus such as a copying machine and, more particularly, relates to a system for self-diagnosing the recording apparatus in which copy jobs are performed to conduct an automatic fault check and other various checks.
Recording apparatus such as copying machines, facsimile machines, and printers of recent development feature high-quality image reproduction and multiple function performance thanks to the introduction of a computer which provides high control and video data processing technology. Such technology also contributes to improving the reliability of these recording apparatus so remarkably that their features are shared with devices of various other fields.
However, there is no apparatus that is free from trouble. It may fault or stop, or its image quality may be impaired. Causes may be secular change, breakage of parts due to life, parameter setting errors, jamming, toner shortage, and so on. In fact, control of the hardware and software of the recording apparatus, being so sophisticated, requires intervention by specialized service men except for cases in which the user can eliminate the trouble by clearing a jam or replenishing the toner, or the like. Thus, the service man must often check the machine with instruments such as a tester to remove the trouble.
However, a color copying machine capable of processing digital images with various editing functions requires a highly sophisticated control, and thus it is extremely difficult and also time-consuming to identify the trouble with instruments such as a tester and an oscilloscope. With respect to trouble in an electronic circuit, it is necessary to find a defective board because the measure to be taken in such a case is per-board replacement. However, circuit boards installed in a newly developed recording apparatus have a multiplicity of circuit elements such as a central processing unit (CPU), for instance and its complicated inter-board communication requires a time-consuming job of locating a defective board with a tester and the like, making its downtime longer.
To overcome this problem, it is important to reduce service time. The decreased service time leads not only to reduction in machine downtime but also to increasing the number of machines to be taken care of by the service man, thereby contributing to saving the maintenance cost and, in the end, reducing the overall running cost on the part of the user.
While the recording apparatus is generally provided with a self-diagnosing mode (hereinafter referred to simply as "diag. mode" for "diagnostic mode"), the diag. mode of the conventional recording apparatus does not allow the copy function to be performed, thus making it quite inconvenient for the following reason. The user often wishes to copy on a trial basis after a check for identifying a defect or after various adjustments to see if that check or adjustments have been performed as prescribed by the user. Lack of the copy function in the conventional diag. mode does not respond to the user's needs. Thus, in the conventional apparatus it is required, to perform copying for confirmation, that the apparatus exit from the diag. mode and return to the normal copy mode, causing a billing problem.